How is it a myth when we know other models on OF do this? She may not be making porn, but that doesn't mean she isn't creating more explicit content specifically for her biggest spenders.
I was actually subscribed to this model (does similar content as KTS) and spent a considerable amount on her PPV content. Then one day, she sent out a DM saying that her special VIPs would be receiving content that she doesn't send to the general subscriber base. I reached out and asked how I could become a VIP, and she told me that I would need to have spent a significant amount on her over the years. She specifically said the threshold was $5,000 or more.
So based on my own experience, I don't think it's unreasonable to believe that high-spending subscribers can get access to content that isn't available to everyone else.